1. Field of the Invention:
The present invention relates to a pump equipment having plural rotary pumps and a method for assembling the pump equipment. In particular, the present invention is preferably applied to an internal gear pump such as a trochoid pump or the like for brake apparatus for vehicles.
2. Description of Related Art:
A rotary pump, for example, an internal gear pump, is comprised of a drive shaft to be driven by a motor, an inner rotor and an outer rotor to be rotated by the drive shaft and a casing for containing the drive shaft and the inner and outer rotors. The casing is provided with a pump room in which the inner and outer rotors are contained, an intake port and a discharge port for sucking and discharging oil and a shaft hole communicating to the pump room from the motor side. The drive shaft is fitted into the inner rotor through the shaft hole.
As an example of the pump in which two rotary pumps are rotated by a drive shaft, a tandem pump equipment is described in JP-A-H.9-126157. In the tandem pump equipment, the discharge ports of the two rotary pumps are provided, respectively, in the same direction from the drive shaft and the intake ports, respectively, in the same direction from the drive shaft, but in the opposite direction from the respective discharge ports. Each pressure at the respective discharge ports of the two rotary pumps is reacted in the same direction against the drive shaft and the drive shaft receives an unbalance force so that the pump operation may be adversely affected due to the bending of the shaft.